import React, { Component } from 'react'
export default class Count extends Component {
  increment = () => {
    const { value } = this.selectNum
    this.props.add(value * 1)
  }
  decrement = () => {
    const { value } = this.selectNum
    this.props.jian(value * 1)
  }
  incrementIfOdd = () => {
    const { value } = this.selectNum
    if (this.props.count % 2 !== 0) {
      this.props.add(value * 1)
    }
  }
  incrementAsync = () => {
    const { value } = this.selectNum
    this.props.addAsync(value * 1, 500)
  }
  render() {
    return (
      <div>
        <h1>当前求和为：{this.props.count}</h1>
        <select ref={c => this.selectNum = c}>
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
        </select>&nbsp;
        <button onClick={this.increment}>+</button>&nbsp;
        <button onClick={this.decrement}>-</button>&nbsp;
        <button onClick={this.incrementIfOdd}>incrementIfOdd</button>&nbsp;
        <button onClick={this.incrementAsync}>incrementAsync</button>
      </div>
    )
  }
}
